Epoxy resins are of particular interest for metal to metal bonding because of their high strength and ability to adhere strongly to metal surfaces. Epoxy resins possess a number of properties which make them uniquely suited for bonding structural components such as low viscosity, low shrinkage, high mechanical strength, flexible range of curing temperatures depending on curing agent selection, solventless curing process, and excellent chemical resistance.
Despite the unique combination of properties possessed by epoxy resins, their versatility has not been fully utilized. The use of epoxy resins has been generally limited to non-load bearing or low load bearing applications. There are a number of factors involved but one of the major reasons is the bond sensitivity of these resins to high humidity or water, particularly hot water. The strength of dry epoxy/metal systems is typically adequate for most structural applications.
There are a number of potential applications where epoxy resins could be used to bond steel substrates of the water sensitivity problem were solved, such as in the automobile and bridge industries.